The present invention relates to surface grinders and more particularly to a surface grinder incorporating an automatic control system.
Various types of surface grinders are commercially available. A typical grinder includes a bed or base upon which a table is mounted for reciprocating motion. A vertical column is secured to the base and a spindle is adjustably mounted on the column for vertical movement A grinding wheel is fixed to the spindle. A work piece or part is secured to the table by means of a magnetic chuck or other fixture. The table may be moved under the wheel manually with a rack and pinion drive and through an hydraulic actuator. To remove material from the work piece or part, the vertical position of the spindle is set and the table is moved to bring the work piece into contact with the grinding wheel. In order to work on parts which are wider than the width of the wheel, most surface grinders also incorporate a cross-feed mechanism which moves the column transversely with respect to the bed. Examples of prior surface grinders may be found in U.S. Pat. No. 2,986,852 entitled GRINDING MACHINES which issued on Jun. 6, 1961 to Wilson; U.S. Pat. No. 3,670,457 entitled ADJUSTABLE TRAVERSE CONTROL FOR SURFACE GRINDER which issued on Jun. 20, 1972 to Berkholcs; U.S. Pat. No. 3,829,750 entitled SELF-ADAPTIVE PROCESS CONTROL which issued on Aug. 13, 1974 to Centner et al; and U.S. Pat. No. 4,485,594 entitled SURFACE GRINDING MACHINE which issued on Dec. 4, 1984 to Guertin et al.
Prior surface grinders have included manual and automatic control systems. The automatic control systems typically include a computer numerical control or CNC device. A control system is disclosed, for example, in U.S. Pat. No. 4,810,945 entitled NUMERICAL CONTROL FEED DEVICE FOR MACHINE TOOL which issued on Mar. 7, 1989 to Yoneda et al. Prior computerized control systems have been relatively expensive and complicated. Such are generally used therefore with machines adapted to grind complex configurations with tight tolerances.
In certain industries such as the carbide insert manufacturing industry, difficulties are encountered with maintaining production rates and quality when the part or work piece is ground using manual control of the surface grinder. The nature of the carbide insert parts being fabricated and the nature of the industry is such, however, that complex and expensive numerically controlled grinders are not cost justified. The shapes and profiles formed are not sufficiently complex to dictate or mandate the use of such machines. Also, such machines require extensive operator training for proper operation. Typically, carbide inserts are ground on manually controlled machines and the benefits of improved quality and increased productivity through automation are not obtained. A need exists, therefore, for a surface grinder having a control system capable of achieving desired quality with improved production rates but which is relatively inexpensive to manufacture and which does not require extensive operator training for proper use.